Open Column Launch Engine from Kit
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mklotz
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For future reference...
The penultimate indicator holder for the mill is the "Zero-Set"
http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=12387423&PMAKA=326-1124
IMNSHO it's the absolute best design since it's rigid, capable of holding the DTI in several ways, has a wide effective range and has a fine adjustment so you don't have to futz around tweaking the indicator stem to get the needle in the middle of the range.
Unfortunately, at ~$200 a pop, they're out of the "sensible" range for most folks, myself included. The options are to:
make your own - a lot of time for a seldom-used tool and an unrealistic task for a novice
just starting out
buy a cheap Chinese knock-off and fine tune it - what I did and works well. Not quite as smooth as the Cadillac model but that doesn't matter since the adjustment remains stationary after setting. It is, after all, merely a dongle to hold a DTI in a given location relative to the mill axis.
I can't immediately find a URL for the knock-off style but look around. They're out there.
Now, back to centering the RT.
First thing, as always in this trade, think about how accurately it must be centered for the job at hand. Will being off a couple of thou really matter? There are an awful lot of jobs out there where it won't. So let's consider some techniques that produce reasonable accuracy and don't even require a DTI.
Make a plug to fit the hole in your table. If the hole has a Morse taper, cut the tang end of an old MT drill or, alternately, buy an MT arbor - they're cheap. If the hole is cylindrical, simply turn a close-fitting plug. Drill and ream this plug 1/4" so a hardened alignment pin will fit into it. At the bottom of this hole drill and tap for something like an 8-32 screw. (More on the reason for this later.) Pop this plug in the RT hole.
Now, some ways to use this...
1. Put a 1/4" pin in the MM chuck/collet and fiddle the RT position until the pin slides freely into the hole in the plug.
2. Put your double-ended edge finder in the chuck/collet and seat the pointy end in the hole in the plug. Fiddle the RT until you can't feel any offset in the edge finder (note: mill not powered while doing this). Your fingers are incredibly sensitive and can detect much less than a thou offset. You can also use this option to fine tune a rough alignment done with #!.
3. Use the edge finder in conventional manner to perform the Osborne maneuver on the outer surface of the plug. (You can read about this maneuver on my website - OSBORNE.ZIP)
I prefer option #2 but any of these will work without a DTI. (I've made a lot of model engine parts on the RT and hardly ever used a DTI to align it.)
Nuances...
If the end of your plug sits below the RT table surface as mine does (rules out option #3), then you can make various custom pins to fit in the 1/4" hole and drop your part (that has a hole at the desired center of rotation) on the pin for automatic part centering on the table. The plug stays in place while you machine the part.
If your plug must be removed after centering and before mounting part to be machined, it may be difficult to get it out of the RT hole. (Especially so if the plug sits below flush as mine does.) This is where that 8-32 thread at the bottom of the hole becomes important. Fashion a miniature slide hammer from a length of 8-32 threaded rod and a chunk of heavyish scrap, thread into plug and pop that baby out without having to access the bottom of the table.
OK, maybe this is a bit more than Carl (or many of you other reader/lurkers) wanted to know (I've been accused more than once of providing "drinking from a fire hose" answers) but, remember that I'm trying to turn this thread into a sort of mini-course for the novice trying to build his first engine and learning stuff that will help him down the line even if he doesn't do it all right now. Remember, too much information is like too much cheese cake - it's just not possible.
The penultimate indicator holder for the mill is the "Zero-Set"
http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=12387423&PMAKA=326-1124
IMNSHO it's the absolute best design since it's rigid, capable of holding the DTI in several ways, has a wide effective range and has a fine adjustment so you don't have to futz around tweaking the indicator stem to get the needle in the middle of the range.
Unfortunately, at ~$200 a pop, they're out of the "sensible" range for most folks, myself included. The options are to:
make your own - a lot of time for a seldom-used tool and an unrealistic task for a novice
just starting out
buy a cheap Chinese knock-off and fine tune it - what I did and works well. Not quite as smooth as the Cadillac model but that doesn't matter since the adjustment remains stationary after setting. It is, after all, merely a dongle to hold a DTI in a given location relative to the mill axis.
I can't immediately find a URL for the knock-off style but look around. They're out there.
Now, back to centering the RT.
First thing, as always in this trade, think about how accurately it must be centered for the job at hand. Will being off a couple of thou really matter? There are an awful lot of jobs out there where it won't. So let's consider some techniques that produce reasonable accuracy and don't even require a DTI.
Make a plug to fit the hole in your table. If the hole has a Morse taper, cut the tang end of an old MT drill or, alternately, buy an MT arbor - they're cheap. If the hole is cylindrical, simply turn a close-fitting plug. Drill and ream this plug 1/4" so a hardened alignment pin will fit into it. At the bottom of this hole drill and tap for something like an 8-32 screw. (More on the reason for this later.) Pop this plug in the RT hole.
Now, some ways to use this...
1. Put a 1/4" pin in the MM chuck/collet and fiddle the RT position until the pin slides freely into the hole in the plug.
2. Put your double-ended edge finder in the chuck/collet and seat the pointy end in the hole in the plug. Fiddle the RT until you can't feel any offset in the edge finder (note: mill not powered while doing this). Your fingers are incredibly sensitive and can detect much less than a thou offset. You can also use this option to fine tune a rough alignment done with #!.
3. Use the edge finder in conventional manner to perform the Osborne maneuver on the outer surface of the plug. (You can read about this maneuver on my website - OSBORNE.ZIP)
I prefer option #2 but any of these will work without a DTI. (I've made a lot of model engine parts on the RT and hardly ever used a DTI to align it.)
Nuances...
If the end of your plug sits below the RT table surface as mine does (rules out option #3), then you can make various custom pins to fit in the 1/4" hole and drop your part (that has a hole at the desired center of rotation) on the pin for automatic part centering on the table. The plug stays in place while you machine the part.
If your plug must be removed after centering and before mounting part to be machined, it may be difficult to get it out of the RT hole. (Especially so if the plug sits below flush as mine does.) This is where that 8-32 thread at the bottom of the hole becomes important. Fashion a miniature slide hammer from a length of 8-32 threaded rod and a chunk of heavyish scrap, thread into plug and pop that baby out without having to access the bottom of the table.
OK, maybe this is a bit more than Carl (or many of you other reader/lurkers) wanted to know (I've been accused more than once of providing "drinking from a fire hose" answers) but, remember that I'm trying to turn this thread into a sort of mini-course for the novice trying to build his first engine and learning stuff that will help him down the line even if he doesn't do it all right now. Remember, too much information is like too much cheese cake - it's just not possible.
zeeprogrammer
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Somehow lost my reply...I'll try again...
Thanks Bob. Your assumptions are correct. But I don't have a 'boo-boo' JT33 project. Or a successful one for that matter.
Thanks for including the instructions on how to use.
Thanks Robert. Looks very helpful. I'll spend more time on it this evening.
Thanks Marv. That's basically the conflict. There's getting the job done and there's using a method as a learning opportunity. I'm trying to hold for the learning but I have a deadline coming up. The deadline is self-imposed...I hope to show the engine off when some family come to visit in a week or two. (Most of the family can't believe I'm doing this. I don't understand why.) In any case...I'll think about the ideas you and the others have provided and see what I can do.
Thanks all.
90LX_Notch said:
Thanks Bob. Your assumptions are correct. But I don't have a 'boo-boo' JT33 project. Or a successful one for that matter.
Thanks for including the instructions on how to use.
Foozer said:
Thanks Robert. Looks very helpful. I'll spend more time on it this evening.
mklotz said:
Thanks Marv. That's basically the conflict. There's getting the job done and there's using a method as a learning opportunity. I'm trying to hold for the learning but I have a deadline coming up. The deadline is self-imposed...I hope to show the engine off when some family come to visit in a week or two. (Most of the family can't believe I'm doing this. I don't understand why.) In any case...I'll think about the ideas you and the others have provided and see what I can do.
Thanks all.
mklotz said:
A word I had to look up, way out of my english language range
I know its ZEE's thread but have a relevant query
Ok, I get the plug and pin route for the close enough projects and the indicate till true for those needing spot on. I'm lathe bound, no mill, have a little 3 inch RT mounted on a cross slide attachment. Turned a plug for the RT center hole that has a small 60 degree nose on it. I set a clean turned round between these centers (lathe spindle dead center and RT plug center) and indicate with the magnetic holder off that to establish the RT position. Seems to work, does it sound right?
Thanks
'pecialy when its swathed with whipped cream and strawberries
mklotz
Well-Known Member
Found it!
This old thread from the HSM site...
http://bbs.homeshopmachinist.net/showthread.php?t=25151&highlight=zeroit1
shows my knock-off Zero-Set as well as a particularly simple way to mount a DTI for easy adjustability.
This old thread from the HSM site...
http://bbs.homeshopmachinist.net/showthread.php?t=25151&highlight=zeroit1
shows my knock-off Zero-Set as well as a particularly simple way to mount a DTI for easy adjustability.
mklotz
Well-Known Member
"Seems to work" and you're asking me if it sounds right? I think you've answered your own question.
In effect, what you're doing is setting up a pump center which is my preferred way of centering stuff in the 4jaw.
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Carl,
I didn't convey this well. You would indicate the MT bore of your RT. Then the mill would be centered to the axis of the RT as 0,0. I don't have a RT yet. I used the JT33 because it was the closest thing to a MT1 or MT2 dia. I could throw in the mill for illustration purposes. The idea was to show that for the required MT dia., your DTI should be able to cover it without having to make a custom holder.
I think it took me less then 10 mins. to throw the JT33 in the vice, mount the indicator in the mill, set the idicator and zero the mill to the center axis of the JT33.
Bob
I didn't convey this well. You would indicate the MT bore of your RT. Then the mill would be centered to the axis of the RT as 0,0. I don't have a RT yet. I used the JT33 because it was the closest thing to a MT1 or MT2 dia. I could throw in the mill for illustration purposes. The idea was to show that for the required MT dia., your DTI should be able to cover it without having to make a custom holder.
I think it took me less then 10 mins. to throw the JT33 in the vice, mount the indicator in the mill, set the idicator and zero the mill to the center axis of the JT33.
Bob
DavesWimshurst
DavesWimshurst
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Carl,
If a burr on the piston is the problem you need to remove it. If you make the cylinder larger to accommodate the burr it will be loose when the burr wears off during the first minutes of running. Lap the cylinder if it's not smooth enough but then you'll probably need to make a new bigger piston.
Filing
I would chuck it in the lathe and using a fine file gently file off the burr. This can be dangerous so I usually do it left handed holding the handle of the file in my left hand and the tip in my right so I don't work over the chuck. Don't wear rings, watches, long sleeves, jewelry etc when doing this!
Sanding
Perhaps safer would be to use something like an emery board stolen from your wife. You could make one from a popsicle stick with fine wet-dry paper glued on it. You can also use a strip of fine wet paper backed up by your 6" pocket rule.
Time travel
When parting off a part like your piston I like to start the parting cut then back the tool out, chamfer, deburr with fine file then finish the parting off action. Voila no burrs!
Whatever you do be careful when using hand tools near a spinning chuck. It is best to use a collet chuck for this if you have one.
Dave
If a burr on the piston is the problem you need to remove it. If you make the cylinder larger to accommodate the burr it will be loose when the burr wears off during the first minutes of running. Lap the cylinder if it's not smooth enough but then you'll probably need to make a new bigger piston.
Filing
I would chuck it in the lathe and using a fine file gently file off the burr. This can be dangerous so I usually do it left handed holding the handle of the file in my left hand and the tip in my right so I don't work over the chuck. Don't wear rings, watches, long sleeves, jewelry etc when doing this!
Sanding
Perhaps safer would be to use something like an emery board stolen from your wife. You could make one from a popsicle stick with fine wet-dry paper glued on it. You can also use a strip of fine wet paper backed up by your 6" pocket rule.
Time travel
When parting off a part like your piston I like to start the parting cut then back the tool out, chamfer, deburr with fine file then finish the parting off action. Voila no burrs!
Whatever you do be careful when using hand tools near a spinning chuck. It is best to use a collet chuck for this if you have one.
Dave
mklotz said:"Seems to work" and you're asking me if it sounds right? I think you've answered your own question.
In effect, what you're doing is setting up a pump center which is my preferred way of centering stuff in the 4jaw.
Thanks, sometimes I fall into the "Hitting a stick of dynamite with a hammer seems to work" mindset, but sounding right. One Darwin award I could do without
Zee,
Going back to the columns in the vise:
When you have them flat to flat they may not all be the same diameter. If you put a piece of construction paper on the movable jaw it will take up any small irregularity you may have. If not, try doubling it. If they stick up high in the vise you can clam 2 parallels or 123 blocks on either side to help "extend" the jaws of your vise. It will still be unstable and small cuts will be needed but the blocks will be against the vise top and will help the tendency for deflection.
Kantwist clamps are the best for this as they pull up very square: http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=505-4544&PMPXNO=945684
Looking good, can't wait till you are spinning it!
Sean
Going back to the columns in the vise:
When you have them flat to flat they may not all be the same diameter. If you put a piece of construction paper on the movable jaw it will take up any small irregularity you may have. If not, try doubling it. If they stick up high in the vise you can clam 2 parallels or 123 blocks on either side to help "extend" the jaws of your vise. It will still be unstable and small cuts will be needed but the blocks will be against the vise top and will help the tendency for deflection.
Kantwist clamps are the best for this as they pull up very square: http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=505-4544&PMPXNO=945684
Looking good, can't wait till you are spinning it!
Sean
mklotz said:
That is just too clever. Love them elegant solutions, Now if the came in DayGlow Pink I'd never loose it.
mklotz
Well-Known Member
All good advice, Dave. Especially the part about using a collet chuck.
Some further safety notes on filing/sanding in the lathe.
Never, not ever, use a file that doesn't have a handle. If it catches on a chuck jaw, that sharp file tang will be driven into your hand or your abdomen. Neither is a good idea.
Even if you're right-handed, hold the file handle in your left hand and the file tip in your right to avoid arching your left arm over the spinning chuck.
Even safer is run the lathe in reverse (turning CW when looking at the chuck) and file from back to front. This way, if the chuck catches the file it will throw it away from you rather than towards you.
Never use a long strip of emery cloth to sand/polish. It's too easy for it double-wind around the work, trap a finger, and suck you in. Use a short (3-4") piece and hold it gingerly with your fingertips so that, if it snags, it will be snatched from your grasp.
Never wrap the emery cloth around your finger or hand while sanding.
Never, no never, attempt to sand the inside of a bore. Your fingers do not have universal joints where they join the hand.
Some further safety notes on filing/sanding in the lathe.
Never, not ever, use a file that doesn't have a handle. If it catches on a chuck jaw, that sharp file tang will be driven into your hand or your abdomen. Neither is a good idea.
Even if you're right-handed, hold the file handle in your left hand and the file tip in your right to avoid arching your left arm over the spinning chuck.
Even safer is run the lathe in reverse (turning CW when looking at the chuck) and file from back to front. This way, if the chuck catches the file it will throw it away from you rather than towards you.
Never use a long strip of emery cloth to sand/polish. It's too easy for it double-wind around the work, trap a finger, and suck you in. Use a short (3-4") piece and hold it gingerly with your fingertips so that, if it snags, it will be snatched from your grasp.
Never wrap the emery cloth around your finger or hand while sanding.
Never, no never, attempt to sand the inside of a bore. Your fingers do not have universal joints where they join the hand.
mklotz
Well-Known Member
Thoughts on gang-milling four hex rods...
Cylindrical scrap piece shorter than the rods. Drill (axial) hole large enough to just accept all four rods. Drill and tap radial hole in scrap to accept jam screw. Insert rods (with their ends protruding from both ends of the scrap piece) and tighten jam screw until all four rods are rigidly retained in scrap piece. Test retention with finger pressure.
Grasp in mill vise so ends of rods are accessible to end mill. Some packing pieces may be necessary to achieve this. Mill one end of rods to make even, mill other end to even, measure, mill to target size.
or, in the lathe...
Grasp scrap in lathe 3jaw. Machine rod ends. Reverse scrap in chuck, take evening cut, remove and measure rod length, reinsert in lathe and trim to target size.
Cylindrical scrap piece shorter than the rods. Drill (axial) hole large enough to just accept all four rods. Drill and tap radial hole in scrap to accept jam screw. Insert rods (with their ends protruding from both ends of the scrap piece) and tighten jam screw until all four rods are rigidly retained in scrap piece. Test retention with finger pressure.
Grasp in mill vise so ends of rods are accessible to end mill. Some packing pieces may be necessary to achieve this. Mill one end of rods to make even, mill other end to even, measure, mill to target size.
or, in the lathe...
Grasp scrap in lathe 3jaw. Machine rod ends. Reverse scrap in chuck, take evening cut, remove and measure rod length, reinsert in lathe and trim to target size.
mklotz said:
Like this perhaps or at least thats what i get from the description, piece of scrap round as chaffing material. Set assembly in vise and trim ends to size, right? right!
vlmarshall
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Oops! That double-space before "Guinness" was supposed to contain an "A". I don't share Guinness well. ;Dzeeprogrammer said:
Ha, I've gotta try that. I've learned something today!Foozer said:
mklotz said:
Too true. This one almost got me years ago, with a strip of cloth-backed emery paper. Not fun. Listen to Marv.
zeeprogrammer
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I was only gone a few hours!!! (I forgot to log off when I went back to work...apologies to anyone who thought I was online.)
Marv: The dial indicator on a magnet...cool. I'll remember that.
Bob (90XL_Notch): You conveyed well. But no...the circle described by the indicator when in the collet is much smaller than the circle in the RT. I have to offset it somehow (like Marv's cool idea) or mount a smaller circle in the RT.
One thing I said in my reply (that didn't get posted) was...the instructions said to center the rotary table and then mount the 3-jaw chuck. I'm wondering why I couldn't mount the 3-jaw chuck and then center on with that. Not that it does me much good.
Dave: Yes. I was going to work the piston first. It fit once...it should again.
Dave and Marv: Regarding the file...I'm either surprised or not understanding...(first...I think Marv's suggestion to run in reverse is the way to go...but in any case)...I had been filing with my left hand holding the 'tip' (the business end) and my right hand holding the handle. Chuck turning CCW seen from the tailstock. That way, my right hand (being over the work) was further away and if things got away...it wouldn't be the handle coming at me. Further, I run slow. The tip of my file is square and at least 1/2" wide. If I run in reverse (CW from tailstock) I would hold the handle with my left hand and the tip with my right. Wouldn't I? Seems like better control to have more resistance against the more substantial tip.
Dave: When I parted...I cut part way in then used a triangular file to chamfer the piston's edge. Then finished the part.
Dave: Why is it better to use a collet chuck?
Sean: Thanks. And thanks for the tip and the link.
Back to the file (the abrasive type)...I've been doing it that way because I read it in a book.
LESSON: Just because a book (or instruction manual) tells you to do it one way...doesn't mean it's the best or the safest. Get as much input as you can and use common sense.
Oh and Marv...we can say what we want about 'instruction books'...but isn't what everyone is suggesting an 'instruction'. It's not the book...it's the quality of advice and that goes for people too. Luckily...this forum provides very good quality.
Marv and Robert: Good tip on ganging. Especially if I'd been doing both ends. Seems a bit more difficult if one end was already done and I was trying to match.
Marv: I must admit I'm guilty of long strips of emery cloth. Thank you.
Never stick a finger in a hole. Goes for wet willies too.
Vernon: Too late with the 'a Guinness'...you've set expectations. I consider the offer to still be open.
Thanks all.
Showed some of the parts off at work today. They were suitably impressed. Course. they don't know the stories behind them like you all do. Ah...it's only a wart if you know about it.
Marv: The dial indicator on a magnet...cool. I'll remember that.
Bob (90XL_Notch): You conveyed well. But no...the circle described by the indicator when in the collet is much smaller than the circle in the RT. I have to offset it somehow (like Marv's cool idea) or mount a smaller circle in the RT.
One thing I said in my reply (that didn't get posted) was...the instructions said to center the rotary table and then mount the 3-jaw chuck. I'm wondering why I couldn't mount the 3-jaw chuck and then center on with that. Not that it does me much good.
Dave: Yes. I was going to work the piston first. It fit once...it should again.
Dave and Marv: Regarding the file...I'm either surprised or not understanding...(first...I think Marv's suggestion to run in reverse is the way to go...but in any case)...I had been filing with my left hand holding the 'tip' (the business end) and my right hand holding the handle. Chuck turning CCW seen from the tailstock. That way, my right hand (being over the work) was further away and if things got away...it wouldn't be the handle coming at me. Further, I run slow. The tip of my file is square and at least 1/2" wide. If I run in reverse (CW from tailstock) I would hold the handle with my left hand and the tip with my right. Wouldn't I? Seems like better control to have more resistance against the more substantial tip.
Dave: When I parted...I cut part way in then used a triangular file to chamfer the piston's edge. Then finished the part.
Dave: Why is it better to use a collet chuck?
Sean: Thanks. And thanks for the tip and the link.
Back to the file (the abrasive type)...I've been doing it that way because I read it in a book.
LESSON: Just because a book (or instruction manual) tells you to do it one way...doesn't mean it's the best or the safest. Get as much input as you can and use common sense.
Oh and Marv...we can say what we want about 'instruction books'...but isn't what everyone is suggesting an 'instruction'. It's not the book...it's the quality of advice and that goes for people too. Luckily...this forum provides very good quality.
Marv and Robert: Good tip on ganging. Especially if I'd been doing both ends. Seems a bit more difficult if one end was already done and I was trying to match.
Marv: I must admit I'm guilty of long strips of emery cloth. Thank you.
Never stick a finger in a hole. Goes for wet willies too.
Vernon: Too late with the 'a Guinness'...you've set expectations. I consider the offer to still be open.
Thanks all.
Showed some of the parts off at work today. They were suitably impressed. Course. they don't know the stories behind them like you all do. Ah...it's only a wart if you know about it.
I'd be real tempted to set a stop on the mill vice and cut the parts to length one at a time versus ganging them.
Touch off the stop, drive the X-axis over the length needed and cut the first one. Wind the Y-axis back, drop the next one in the stop and crank over on Y again... rinse, repeat.
Touch off the stop, drive the X-axis over the length needed and cut the first one. Wind the Y-axis back, drop the next one in the stop and crank over on Y again... rinse, repeat.
vlmarshall
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zeeprogrammer said:Vernon: Too late with the 'a Guinness'...you've set expectations. I consider the offer to still be open.
Print Attached File. Cut. Fold. Glue.
I made that a few years ago as a joke... finally it comes in handy. ;D
View attachment GuinnessExtraStoutBottle4.pdf
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shred said:
That's how I would do it on a mill. For the columns on my current build I measured each with the height gauge and faced to length on the lathe, mainly because I needed to drill and tap the ends afterwards.
zeeprogrammer
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shred said:
More than tempted. A vise stop is on my "need to purchase, make, or obtain by any legal (he says) means)" list of tools. It may be the one tool that has come up more often in this thread than any other.
Thanks shred.
Just saw your post kvom. My columns already had one end threaded. Would that have made a difference to your approach? Did you mark the columns with the height gauge? (How?)
Vernon...? [EDIT: Oh...I saw the attachment after I posted. That's great. Can I use it? I have a certain son-in-law...I see the opportunity for some fun. But it don't let you off...everyone on this forum knows what you meant. ;D]
